I will duplicate answer here also (also it was sent as email from support)

Polarion stores project templates in two places with one that overrides the other. The master location that overrides the slave location is stored in the repository at /.polarion/projects/templates. The slave location is on disk within the Polarion installation tree for instance: C:\Polarion\polarion\plugins\com.polarion.alm.projects_3.4.1\templates. The slave location will be used when there are no templates stored in the Repository.You can import into the repository one of the templates and then make use of the template or checkout the template and make changes to it.